(a) Technical Field of the Invention
The present invention generally relates to a chair's armrests, and more particularly to armrests whose lateral position and orientation are adjustable.
(b) Description of the Prior Art
For seating comfort, there are various types of chairs whose backrests and seats can be raised and lowered to fit the particular posture of a user. One such chair is illustrated in FIG. 1. As depicted, the seat 11 is fixedly mounted perpendicularly to an end of a threaded shaft 13 whose other end is screwed into a base 14 of the chair 1. When the seat 11 is spun relative to the base 14, the seat 11 can be raised or lowered. On the other hand, a backrest 15 of the chair 1 has a jacket 17 at the back wrapping around an elongated plug 18 at an end of a flexible belt extended from the bottom of the seat 11. The backrest 15 can be slid along the plug 18 so as to reach an appropriate height. Then, a twisting knob 16 is used to tightly clip the jacket 17 and the plug 18 together.
As shown in FIG. 1, the chair 1 has a pair of arm resting devices 12 fixedly attached to two lateral sides of the seat 11 respectively. The arm resting devices 12 are therefore raised or lowered together with the seat 11. FIG. 2 shows another conventional arm resting device 2 which can be raised or lowered independently. As illustrated, the arm resting device 2 contains a resting element 21 having a flat and extended top portion for supporting a user's arm and a bottom portion for receiving a plug 221 at an end of an L-shaped leg 22 whose other end is attached to the seat (not shown). The resting element 21 can be slid along the plug 221 so as to reach an appropriate height. Then, a twisting knob 23 is used to tightly and fixedly join the resting element 21 and the plug 221 together at the particular height.
Even though the arm resting device 2 described above can be raised or lowered individually and independently, it cannot be adjustably shifted towards the front or the back of the chair, or turned to the left or the right of the chair so as to provide improved seating comfort.